You are referring to section 5.2.1 if I am not correct, not 3.2.1?

The context is important here. 5.2.1 is discussing using the variable as part of your local.conf. Which is
a different animal then adding it to an image recipe.  In local.conf you really need _append to for it to
even take effect, where its more correct and natural in my opinion to use += in bb since it provides
more flexibility to alter the recipe with out using too much magic.

  again, some nitpickiness, but in the current YP dev manual, section
3.2.1, the manual is quite explicit about using "_append" with
IMAGE_INSTALL:

"Furthermore, you must use _append instead of the += operator if you
want to avoid ordering issues."

  the way that's worded, that's not just a recommendation, it's a
pretty clear directive to the reader, which flies in the face of an
admittedly small number of examples of that in current OE:

$ grep -r "IMAGE_INSTALL +=" *
meta/recipes-sato/images/core-image-sato-ptest-fast.bb:IMAGE_INSTALL += "${PTESTS_FAST}"
meta/recipes-sato/images/core-image-sato-sdk-ptest.bb:IMAGE_INSTALL += "${PTESTS_FAST} ${PTESTS_SLOW}"
meta/recipes-sato/images/core-image-sato-sdk.bb:IMAGE_INSTALL += "kernel-devsrc"
meta/recipes-extended/images/core-image-testmaster.bb:IMAGE_INSTALL += "\
meta/recipes-rt/images/core-image-rt-sdk.bb:IMAGE_INSTALL += "rt-tests hwlatdetect kernel-dev"
meta/recipes-rt/images/core-image-rt.bb:IMAGE_INSTALL += "rt-tests hwlatdetect"
meta/recipes-core/images/core-image-minimal-mtdutils.bb:IMAGE_INSTALL += "mtd-utils"
meta-selftest/recipes-test/container-image/container-test-image.bb:IMAGE_INSTALL += "container-image-testpkg"
meta-skeleton/recipes-multilib/images/core-image-multilib-example.bb:IMAGE_INSTALL += "lib32-bash"
$

  i'm fine leaving things as is, but those few examples clearly fly in
the face of the instruction given in the dev manual.

  thoughts?

rday

-- 
Jeremy A. Puhlman
jpuhlman@...